From Wikipedia, the free encyclopedia

Alien is a computer program that converts between
different Linux package formats. It
supports conversion between Linux Standard Base, RPM, deb,
Stampede (.slp), Solaris (.pkg) and Slackware (.tgz) packages. It is also capable of automatically
installing the generated packages, and can try to convert the
installation scripts included in the archive as well. The latter
feature should be used with caution since Linux
distributions may vary significantly from one another, and
using install scripts automatically converted from an Alien format
may break the system. The Alien tool is specially written for
Linux.

A sample usage of Alien:

# alien --to-rpm --scripts ./mypkg.deb

This will convert mypkg.deb to mypkg.rpm with the preinst,
postinst, prerm and postrm scripts from the Debian package (deb) into the RPM
package.